(SAN BERNARDINO, Calif.) — The older sister of Syed Farook, one of the suspected shooters in Wednesday’s deadly San Bernardino rampage, said she and her husband hope to adopt the 6-month-old baby girl left behind by her brother and his wife, who were both killed by police in a shootout.

“For the time being, we want her to enjoy her innocence,” Saira Khan told ABC News’ Kayna Whitworth. “You know, we don’t want her to know everything, but I think eventually she will find out probably on her own.”

San Bernardino County Sheriff John McMahon told ABC News “federal authorities, in conjunction with the county’s child protective services, took custody of that child, and at some point in the next week, they will have a dependency hearing in the County of San Bernardino to determine where, ultimately, that child will live, at least in the short term.”

The Khans, who have a 2-year-old girl and 7-year-old boy of their own, told ABC News they hope to have their niece by Monday.

Malik, 29, who is from Pakistan but had lived in Saudi Arabia, came to the U.S. last summer on a “fiancé” visa and later obtained a Green Card, U.S. officials have said. Malik married Farook, an American of Pakistani descent, in August 2014 and the couple had a baby daughter six months ago.

Malik and Farook unleashed a deadly attack in San Bernardino on Wednesday, killing 14 people and injuring another 21, an act now being investigated as terrorism.

In the last 21 months, at least 71 people in the U.S. were charged with ISIS-related activities, including 10 women, according to authorities. Some have been mothers, like Malik.

“They’re prioritizing martyrdom above all other aspects of their life, including raising a family,” Audrey Alexander, a fellow with the George Washington University program on extremism, told ABC News’ Martha Raddatz.

“It’s harder for us to understand, especially knowing that he was our brother and he was so happy with her,” Saira Khan said. “How can he leave his only child, you know? And how could the mother do this?”

Saira Khan called Wednesday’s deadly shooting “horrific,” and to the victims, she said, “We can’t begin to imagine what they’re going through.”